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The presence of secondary metabolites in Moringa oleifera is the decisive factor for the green synthesis of silver nanoparticles (AgNPs). Among the metabolites involved in this process, phenols and flavonoids in the plant extract are the two most important groups, acting both as reducing and stabilizing agents. M. oleifera, a well-known herb from Indonesia, was used in this study due to its exceptional properties, such as antioxidant, antimicrobial, and anti-inflammatory among others. The total phenolic content and total flavonoid content in the aqueous extract of M. oleifera leaves were determined, and the values were 62.01 ± 2.05 mg/g and 71.97 ± 0.94 mg/g, respectively. The synthesis factors including pH, extract volume, and temperature for the synthesis of AgNPs were optimized using the onefactor- at-a-time approach. The synthesis experiment showed that a pH of 8.0, an extract volume of 0.3 mL, and a temperature of 80°C resulted in the highest intensity of localized surface plasmon resonance at a wavelength of 419 nm, which favored the synthesis after 24 h of reaction time. Due to the remarkable content of metabolites, M. oleifera can be used as a promising candidate for the effective synthesis of AgNPs.

Microplastics have aroused global concern due to their widespread environmental distribution and the possible danger they pose to humans, animals, and microbes. In response to this concern, photocatalytic degradation, a technique that utilizes semiconductor nanomaterials as the photocatalyst, is being explored to reduce microplastics into less harmful compounds, making it a game-changing strategy for addressing this environmental problem. Besides the superiority of titanium dioxide (TiO2) as a photocatalyst, zinc oxide (ZnO) nanoparticles are also one of the semiconductors that have been widely explored to date. Studies have proven its potential to degrade microplastics in either solid- or aqueous phases. In the photocatalytic degradation of microplastics, the reactive oxygen species (ROS), including hydroxyl (•OH) and superoxide ions (O2•-), play an essential role in the process, resulting in the breakdown of the polymeric chain and the generation of reaction intermediates. Therein, the primary focus of this review is limited to the photocatalytic degradation of microplastics using a ZnO-based photocatalyst and its mechanisms. The exploration and comparison of microplastic's solid- and aqueous-phase photocatalytic processes in terms of their experimental setup and performance were also discussed further. Furthermore, an insight into future research prospects is also suggested here, based on the restrictions of present photocatalytic degradation systems. [ABSTRACT FROM AUTHOR]

Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA)-Mn0.25Fe2,75O4/Ag ferrogels was fabricated by using the freezing-thawing method. Mn0.25Fe2.75O4/Ag magnetic fillers of ferrogels were synthesized by using coprecipitation and chemical reduction methods. Characterization of Mn0.25Fe2.75O4/Ag nanopowders was carried out using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM) instrument, and antimicrobial activity. At the same time, CMC/PVA-Mn0.25Fe2.75O4/Ag ferrogels were characterized by using magnetothermal instrument. The XRD pattern of the magnetite filler shows the peaks by the Fe3O4 and Ag phases, respectively. The TEM image, there are Mn0.25Fe2.75O4 and Ag with particle size distributions of 5–7 and 10–13 nm, respectively. The hysterical curve from VSM characterization shows a decrease in the value of magnetization saturation from 16.9 to 14.7 emu/g along with the addition of Ag material. Antimicrobial activity was tested using the agar diffusion method. Mn0.25Fe2.75O4/Ag samples showed very good results indicated by the widening of the zone of inhibition around the sample. Thus, CMC/PVA-Mn0.25Fe2.75O4/Ag ferrogels has the potential application to be applied in hyperthermia therapy as well as antimicrobial materials. [ABSTRACT FROM AUTHOR]